ACOUSTIC SCATTERING FROM THIN-WALLED CYLINDERS: EXPERIMENTAL VALIDATION OF A NOVEL BOUNDARY ELEMENT METHOD

We measured the monostatic target echo strength (TES) of a thin-walled aluminium cylinder, flooded with water, as a function of azimuth aspect angle and frequency. We present the near field estimate of the TES. Various scattering mechanisms are observed and delineated. In order to facilitate comparison with theory, reduced sets of data points encompassing the most prominent scattering features were chosen. These reduced sets were simulated using a novel Boundary Element Method for acoustically thin targets. As the approach does not take elastic waves into account, a rich comparison is found, with some features being well-accounted for, while others are absent. Of note is the acoustic regime explored, with the cylinder length and radius, L and R, large with respect to the wavelength λ, L,R>> λ, but the wall thickness t is small with respect to the wavelength. This allows us to explore the regime t<<λ that has not been extensively studied in experiment.